America's biggest rocket blasts off, likely carrying spy satellite

A 235-foot-tall rocket carrying a top-secret spy satellite roared to life and blasted off from Vandenberg Air Force Base, leaving a thick white plume as it cut across the morning sky.

The launch took place Wednesday at 11:03 a.m. PDT at the picturesque base, which is located along the Pacific Ocean.

After countdown, the Delta IV Heavy rocket's three main engines ignited and climbed into skies. The hydrogen-fueled engines — each roughly the size of a pickup truck — were guzzling nearly a ton of propellants per second to provide 17 million horsepower.

Although little is publicly known about what exactly the rocket will be carrying into space, analysts said it is probably a $1-billion high-powered spy satellite capable of snapping pictures detailed enough to distinguish the make and model of an automobile hundreds of miles below.

Wednesday’s mission, designated NROL-65, has been on schedule for months.

Although Cape Canaveral, Fla., is the launch site for NASA's civilian space program, Vandenberg has been the site of military space projects for more than half a century.

Vandenberg, a 98,000-acre base along the Pacific, has been the primary site for launching spy satellites since the beginning of the Cold War because of its ideal location for putting satellites into a north-to-south orbit.

Space Launch Complex 6 is known on base as “Slick Six.” The launch pad was built in the 1960s and later was intended to accommodate space shuttle launches, but they remained in Florida. Since then, the pad has gone through many renovations. Most recently, Vandenberg spent $100 million on upgrades over three years.

This is the second time that a Delta IV Heavy rocket was launched from the pad at Vandenberg. The first time was in January 2011.

The rocket was built by United Launch Alliance, a joint venture of Lockheed Martin Corp. and Boeing Co. It made its maiden flight in 2004 and is capable of lifting payloads of up to 24 tons into low Earth orbit.

The launch was streamed live at rocket maker United Launch Alliance's website.